A green and efficient degumming method for ramie fibers: Pectate lyase combined with potassium peroxy(mon)sulfate...

To address the high pollution burden of chemical degumming for ramie fibers and the low efficiency of microbial methods, this study developed a novel synergistic degumming system employing pectate lyase in conjunction with potassium peroxy(mon)sulfate (PPMS). Based on enzymatic characterization, reducing sugar analysis, and immunofluorescence results, pectate lyase (PcPel1834) was identified as the crucial enzyme in degumming strain Pectobacterium carotovorum HG-49. The enzyme exhibited high catalytic efficiency (4980 U/mg, K_cat/K_m = 1588.92 mL·s^-1·mg^-1), and its degumming performance was comparable to that of commercial pectate lyase. The 6.5 h treatment combining PcPel1834 and PPMS, achieved total gum removal rate of 88.72%, bundle breaking tenacity of 5.10 cN/dtex and whiteness of 52.7, meeting the first-class textile criteria of China. The degumming mechanism of the synergistic system was elucidated via immunofluorescence, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and gas chromatography-mass spectrometry (GC/MS) analysis. PcPel1834 efficiently degraded pectin and deconstructed the compact bundle structure of ramie bast fibers. This facilitated PPMS in generating a strong oxidative environment rich in oxygen free radicals, which degraded hemicellulose and lignin into small-molecule acids, benzoic acid and aromatic hydrocarbon fragments. This study established an efficient and eco-friendly degumming paradigm for ramie industry.